This invention relates to a method of modifying a synthetic or natural polyamide product by means of a graft polymerization treatment.
Although various attempts have been made to modify synthetic or natural polyamide-type products by graft polymerization, few methods are industrially feasible and capable of utilizing a graft monomer efficiently. Methods of graft-polymerizing an acidic vinyl monomer to a polyamide-type product are described in various references such as Japanese Patent Publication Nos. 8543/1958, 7248/1959, 9283/1959, and 7834/1960. However, although these methods make it possible to graft the monomer on a laboratory scale, they call for radioactive irradiation or are disadvantageous in that the efficiency of utilization of the monomer (hereinafter called the "grafting efficiency") is as low as 30% or below. Thus, they are not feasible on an industrial scale.